Early-life nutrition has a significant impact on survival rate, health status, and overall performance of young goats. It is essential to have information on both short- and long-term effects of early-life nutrition on offspring performance to correctly evaluate the cost-effectiveness of different nutritional strategies.
Newborn kids (baby goats) are immunologically naive at birth; therefore, they use maternal antibodies absorbed through colostrum consumption to protect them against infectious diseases. As a result, colostrum feeding management is an essential aspect of young goat rearing with long-lasting effects on their growth performance and development.
Goat colostrum contains high levels of fat, protein, immunoglobulin, enzymes, hormones, growth factors, antimicrobial factors, neuroendocrine peptides, and vitamins. Colostrum can be used as a source of energy for growth and thermoregulation and plays a crucial role in the development of passive immunity and maturation of the digestive tract of newborn kids.
Colostrum quality is evaluated based on the immunoglobin G (IgG) concentration which needs to be greater than 8 g/L to lower mortality risks in crossbred kids from 0 to 45 days of age managed under extensive systems. It is recommended to feed kids 150-200 mL of colostrum per kg of bodyweight divided into 2-4 meals, with at least 50-100 mL/kg of bodyweight being fed within 6 hours after birth.
In addition, kids under natural suckling have stronger immune status compared to kids that were fed a single meal of high-quality colostrum within 2 hours postpartum. Furthermore, fractionating colostrum feeding improves gut absorption and increases serum immunoglobulin levels. Although the apparent efficiency of IgG absorption declines rapidly as kids get older.
Natural suckling is the least preferred method because in some cases kids fail to promptly drink enough colostrum, or maternal colostrum does not meet quality standards which increases the risk of failed transfer of passive immunity.
In addition, in goat herds infected with caprine arthritis encephalitis which typically spread from dam to kid via colostrum and milk ingestion, it is recommended to feed newborn kids with pooled colostrum from seronegative goats. Although hand-feeding pooled or non-pooled colostrum decreases the risk of disease spread, managing various factors including colostrum quality, treatment and preservation, time, volume, and frequency of feeding increases workload and labor cost associated with rearing kids. Furthermore, single colostrum feeding is more practical and less time-consuming than carrying out multiple feedings. In case the caprine arthritis encephalitis-free colostrum is unavailable, it is suggested to use colostrum from other ruminants such as sheep, and cattle, or commercial replacers. A colostrum replacer enhances serum IgG concentration above 12 g/L for young goats.
Maternal suckling systems include unrestricted suckling which is mostly used in meat and mohair-producing herds and restricted suckling which is commonly practised in extensive dairy goat systems. Maternal suckling reduces the amount of marketable milk during the suckling period, increases total milk production per lactation, bodyweight gain and survival rate at weaning, and decreases labour costs associated with artificial feeding.
On the other hand, artificial feeding is usually used in intensive dairy systems. During early lactation, restricted maternal suckling accompanied with machine milking is a valuable management tool for dairy goat production. Furthermore, in maternal suckling systems, the contact between dam and kid allows for a natural rumen microbial transfer to the offspring, but in artificial feeding systems kids are separated from their dams shortly after birth which limits the rumen microbial colonisation and development in the offspring.
Considering the high price of goat milk, various less expensive alternatives including whole cow or sheep milk, milk whey, and milk replacer can be used to substitute goat milk. Kids fed calf milk replacer mixed with 65% water and 35% goat milk whey has a similar average daily gain to kids fed whole goat or cow milk, and a higher average daily gain than kids fed cow milk replacer or 50% goat whey. Application of milk whey instead of water to prepare milk replacer mixture decreases the use of commercial milk substitutes by half. Supplementing probiotics decreases susceptibility to enteric diseases, increases nutrient bioavailability and absorption by restoring beneficial gut microbiota, improves immune system function, and lowers the incidence of diarrhoea. Unrestricted milk feeding reduces concentrate consumption and increases the cost of raising kids compared to traditional rearing. In addition, increasing pre-weaning dry matter intake through liquid and/or concentrated diets can have a positive impact on the subsequent milk production.
Kids should have ad libitum access to a good-quality highly palatable concentrate with 18-20% crude protein to stimulate early consumption.
Substituting whole, rolled, or crushed cereal grains with pelleted concentrate increases feed intake, average daily gain, feed conversion ratio, and ruminal development of kids.
Creep feeding provides concentrate and/or forage for the kids and prepares them for a good transition to a solid diet before weaning. In addition, creep feeding increases pre-weaning average daily gain and bodyweight.
From weaning to 4 months of age, the quantity and quality of concentrates is based on the availability of quality forage. From 4 to 9 months of age, concentrate consumption needs to be limited to 600-800 g per kid per day, and from 9 months onwards the concentrate should be gradually substituted by the similar feed distributed to adult pregnant goats.
In addition, forage should be available to kids as soon as possible to promote rumen development and to ensure a smooth transition into a solid diet at the time of weaning. Daily intake of good-quality hay should be at least 200-250 g per day at weaning, however, farmers are encouraged to not offer alfalfa hay to kids younger than 4 months to avoid bloating.
Young goat rearing is a crucial profit driver and the foundation of herd productivity in dairy goat production systems. Early-life nutrition has essential impacts on health, welfare, and production performance of dairy goats and their offspring. However, further research is required to focus on the long-term impacts of early-life nutrition in kids.
* Reference is available upon request.